This invention relates to an improvement in fluid quick connect couplings wherein the various components of the coupling are positioned with a greater degree of accuracy than in the prior art. Moreover, fewer components are required. With the inventive fluid coupling, the o-ring and retainer are positioned such that there will be only one continuous resistance to insertion of a tube.
Quick connect couplings are utilized in the prior art to connect fluid tubes to other fluid components, particularly on vehicles. As used in this application the term xe2x80x9ctubexe2x80x9d refers to any type of fluid carrying line.
Typically, a quick connect coupling includes a retainer with a plurality of resilient legs that flex outwardly to allow passage of an enlarged bead on the tube. The legs flex radially inwardly behind the bead, locking the tube in the component. Although this is the most common type of quick connect coupling, aspects of this inventive do have benefits in other types of couplings.
The use of quick connect couplings in a manufacturing process does present some challenges. In some cases, the assemblers have not fully connected the tube within the quick connect coupling. There is a required insertion force for moving the tube bead beyond the retainer legs to insure that the tube is fully connected by the quick connect coupling. If the quick connect coupling does not fully receive the tube (i.e., the bead does not move beyond the retainer legs), then fluid pressure on the tube, such as will occur during operation of the vehicle, can cause the tube to be blown outwardly of the coupling. This is, of course, undesirable.
Moreover, known quick connect couplings utilize a number of components that each have their own dimensional tolerances. By increasing the number of components, the number of dimensional tolerances, or total xe2x80x9cstack upxe2x80x9d of combined tolerances increases. This makes it difficult to reliably and accurately position the components relative to each other. To this end, it would be desirable to decrease the number of components in a fluid quick connect coupling.
Finally, standard quick connect couplings have a condition where their multiple components create excessive clearances that allow the tube to become off axis from the connector housing. This condition minimizes the effectiveness of the coupling seal. The prior art does not attempt to improve this problem.
In the disclosed invention, a fluid quick connect coupling reduces the number of components over the prior art. This reduces the number of individual dimensional tolerances and consequently the stack-up of dimensional tolerances. In this way, the relative positioning of the several components may be more tightly controlled. By being able to more tightly control the positioning of the components, one is able to achieve certain goals. In addition, by reducing the number of components, the cost and assembly time are also reduced.
One goal achieved by reducing the dimensional stack-up is that relative positioning of the o-ring and the retainer legs may be better optimized. The present invention also optimizes the relative position of the o-ring and the retainer. The o-ring seals the tube, and the retainer legs hold the tube. Both provide resistance to insertion of the tube. The seal resistance is due to compressing the seal. Typically, the seal resistance occurs, then there is a break in resistance, then the retainer leg resistance occurs. In the past, assemblers have sometimes interpreted the resistance force from the seal as being the retainer resistance force. Thus, once the seal resistance force has been overcome, the assembler has stopped further insertion. Such a tube is not fully connected.
The present invention positions the seal relative to the retainer leg such that there is no break between compression of the seal, and beginning to encounter the retainer leg resistance. Thus, an assembler is not given a xe2x80x9cfalse feelxe2x80x9d that by having overcome the seal insertion resistance, the assembler has fully connected the tube. Rather, there is one continuous resistance to insertion. In a preferred embodiment, the seal is positioned such that once seal resistance is overcome, the assembler immediately begins to encounter resistance from the retainer legs.
The use of the reduced number of components, provides valuable benefits in the positioning the o-ring relative to the retainer legs. The manufacturing tolerance stack-up makes it more difficult to accurately position an o-ring relative to the retainer. Thus, the two above-discussed portions of this invention benefit each other.
To achieve the component reduction, a single component is utilized to provide the three functions of an o-ring positioner, a spring holder for a check valve spring, and a stop to prevent undue movement of the check valve. The use of a single component to provide all three of these functions reduces the number of required components.
In other features of this invention, the valve seat has an optimized structure wherein there is a line contact that provides the valve seat, and the valve body is cut away at positions removed from the line contact at the valve seat.
In further features of this invention, a pilot member guides the tube into the housing. The pilot member is formed with compression ribs axially on its outer periphery. These ribs eliminate tolerance stack-up between the pilot and the housing. This is accomplished by the equally spaced ribs compressing evenly and centering the pilot. The compressed ribs tend to bias the pilot, and the evenly centered pilot positions the tube as if the pilot was one piece with the housing. This also benefits the optimization of component positioning.
The various combined features of this invention complement each other and result in a quick connect coupling which provides valuable benefits when compared to the prior art.
These and other features of the present invention can be best understood from the following specification and drawings, of which the following is a brief description.